Observation of inverse magnetocaloric effect in magnetic-field-induced austenite phase of Heusler alloys Ni50-xCoxMn31.5Ga18.5 (x=9 and 9.7) OBSERVATION of INVERSE MAGNETOCALORIC EFFECT ... T. KIHARA et AL.

T. Kihara, T. Roy, X. Xu, A. Miyake, M. Tsujikawa, H. Mitamura, M. Tokunaga, Y. Adachi, T. Eto, T. Kanomata

研究成果: Article査読

抄録

The magnetocaloric effect (MCE), magnetization, specific heat, and magnetostriction measurements were performed in both pulsed and steady high magnetic fields to investigate the magnetocaloric properties of Heusler alloys Ni50-xCoxMn31.5Ga18.5 (x=9 and 9.7). From direct MCE measurements for Ni41Co9Mn31.5Ga18.5 up to 56 T, a steep temperature drop was observed for magnetic-field-induced martensitic transformation (MFIMT), designated as inverse MCE. Remarkably, this inverse MCE is apparent not only with MFIMT, but also in the magnetic-field-induced austenite phase. Specific heat measurements under steady high magnetic fields revealed that the magnetic field variation of the electronic entropy plays a dominant role in the unconventional magnetocaloric properties of these materials. First-principles based calculations performed for Ni41Co9Mn31.5Ga18.5 and Ni45Co5Mn36.7In13.3 revealed that the magnetic-field-induced austenite phase of Ni41Co9Mn31.5Ga18.5 is more unstable than that of Ni45Co5Mn36.7In13.3 and that it is sensitive to slight tetragonal distortion. We conclude that the inverse MCE in the magnetic-field-induced austenite phase is realized by marked change in the electronic entropy through tetragonal distortion induced by the externally applied magnetic field.

本文言語English
論文番号034416
ジャーナルPhysical Review Materials
5
3
DOI
出版ステータスPublished - 2021 3

ASJC Scopus subject areas

  • 材料科学(全般)
  • 物理学および天文学(その他)

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「Observation of inverse magnetocaloric effect in magnetic-field-induced austenite phase of Heusler alloys Ni50-xCoxMn31.5Ga18.5 (x=9 and 9.7) OBSERVATION of INVERSE MAGNETOCALORIC EFFECT ... T. KIHARA et AL.」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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